I've built a linear power booster - schematic here: http://pedalparts.co.uk/docs/LPB-V3.pdf
I did it on veroboard:
You'll note that it gives you the option of having different capacitor values to turn the pedal from a 'clean' boost to a treble booster. Ideally I would like to make one with a 3 way switch - ON-ON-ON (double pole) to be able to switch between capacitors.
Now I just tried this with a 3 way slide switch that looked like this:
Forgive the crude diagram, but it was a 2 pole switch so I used the other pole to do a similar thing with the other cap (C2, not actually electrolytic, just ceramic)
When I tried it, the first position with the high value (100n) cap sounded ok, but the others were choked and thin sounding. It's a guess, but are the other two (unused) capacitors acting like decoupling caps and filtering out loads of the frequencies? The sound is more trebley, but it's very quiet. Is there a better switching mechanism I could use so that I don't have to have 3 capacitors connected to the same place? Maybe a diode or six?